BZOJ1180: [CROATIAN2009]OTOCI

  1 #include<cstdio>
  2 #include<cstdlib>
  3 #include<cmath>
  4 #include<cstring>
  5 #include<algorithm>
  6 #include<iostream>
  7 #include<vector>
  8 #include<map>
  9 #include<set>
 10 #include<queue>
 11 #include<string>
 12 #define inf 1000000000
 13 #define maxn 100000+5
 14 #define maxm 500+100
 15 #define eps 1e-10
 16 #define ll long long
 17 #define pa pair<int,int>
 18 #define for0(i,n) for(int i=0;i<=(n);i++)
 19 #define for1(i,n) for(int i=1;i<=(n);i++)
 20 #define for2(i,x,y) for(int i=(x);i<=(y);i++)
 21 #define for3(i,x,y) for(int i=(x);i>=(y);i--)
 22 #define mod 1000000007
 23 using namespace std;
 24 inline int read()
 25 {
 26     int x=0,f=1;char ch=getchar();
 27     while(ch<‘0‘||ch>‘9‘){if(ch==‘-‘)f=-1;ch=getchar();}
 28     while(ch>=‘0‘&&ch<=‘9‘){x=10*x+ch-‘0‘;ch=getchar();}
 29     return x*f;
 30 }
 31 int n,m,v[maxn],sum[maxn],c[maxn][2],fa[maxn],f[maxn],sta[maxn],top;
 32 bool rev[maxn];
 33 inline int find(int x){return f[x]==x?x:f[x]=find(f[x]);}
 34 inline bool isroot(int x)
 35 {
 36     return c[fa[x]][0]!=x&&c[fa[x]][1]!=x;
 37 }
 38 inline void pushup(int x)
 39 {
 40     sum[x]=sum[c[x][0]]+sum[c[x][1]]+v[x];
 41 }
 42 inline void rever(int x)
 43 {
 44     rev[x]^=1;swap(c[x][0],c[x][1]);
 45 }
 46 inline void pushdown(int x)
 47 {
 48     if(!rev[x])return;
 49     rever(c[x][0]);rever(c[x][1]);
 50     rev[x]=0;
 51 }
 52 inline void rotate(int x)
 53 {
 54     int y=fa[x],z=fa[y],l=c[y][1]==x,r=l^1;
 55     if(!isroot(y))c[z][c[z][1]==y]=x;
 56     fa[x]=z;fa[y]=x;fa[c[x][r]]=y;
 57     c[y][l]=c[x][r];c[x][r]=y;
 58     pushup(y);pushup(x);
 59 }
 60 inline void splay(int x)
 61 {
 62     sta[++top]=x;
 63     for(int y=x;!isroot(y);y=fa[y])sta[++top]=fa[y];
 64     for(;top;)pushdown(sta[top--]);
 65     while(!isroot(x))
 66     {
 67         int y=fa[x],z=fa[y];
 68         if(!isroot(y))
 69         {
 70             if(c[z][0]==y^c[y][0]==x)rotate(x);else rotate(y);
 71         }
 72         rotate(x);
 73     }
 74 }
 75 inline void access(int x)
 76 {
 77     for(int y=0;x;x=fa[x])
 78     {
 79         splay(x);c[x][1]=y;pushup(x);y=x;
 80     }
 81 }
 82 inline void makeroot(int x)
 83 {
 84     access(x);splay(x);rever(x);
 85 }
 86 inline void link(int x,int y)
 87 {
 88     if(find(x)==find(y)){printf("no\n");return;}
 89     printf("yes\n");
 90     makeroot(x);fa[x]=y;f[find(x)]=find(y);splay(x);
 91 }
 92 inline void split(int x,int y)
 93 {
 94     makeroot(x);access(y);splay(y);
 95 }
 96 int main()
 97 {
 98     freopen("input.txt","r",stdin);
 99     freopen("output.txt","w",stdout);
100     n=read();
101     for1(i,n)v[i]=sum[i]=read(),f[i]=i;
102     m=read();
103     while(m--)
104     {
105         char ch[10];
106         scanf("%s",ch);int x=read(),y=read();
107         if(ch[0]==‘b‘)link(x,y);
108         else if(ch[0]==‘p‘)splay(x),v[x]=y,pushup(x);
109         else if(find(x)!=find(y))printf("impossible\n");
110         else split(x,y),printf("%d\n",sum[y]);
111     }
112     return 0;
113 }